Method for the denitrization of hydrocarbon charges in the presence of a polymeric mass

ABSTRACT

A process for denitrogenation of hydrocarbonated compounds containing basic and/or neutral nitrogenous hydrocarbonated compounds characterized by the fact that the hydrocarbonated compounds are placed in contact with a polymeric material including at least one polymer P obtained from at least one non-styrenic monomer A with at least one polar function generating hydrogen bonds with the nitrogenous hydrocarbonated compounds.

BACKGROUND OF THE INVENTION

This invention concerns a denitrogenation process for hydrocarbonated charges in the presence of a polymeric material likely to establish specific bonds with the neutral and basic nitrogenous compounds present in the hydrocarbons. It also concerns polymeric materials adapted to this process and the use of this process upstream of some processing of these hydrocarbonated charges.

The presence of nitrogenous compounds in the petroleum cuts emitted from the distillation of crude oil is well known and has been widely described, for example in the article by D. Tourres, C. Langelier and D. Leborgne titled “Analysis of nitrogenous compounds in petroleum cuts by CPG on a capillary column and specific detection through chemiluminescence,” Analysis Magazine, vol. 23, No. 4, 1995. These nitrogenous compounds are present in a distillation cut in variable quantities according to the nature of the crude oil and according to the initial and final distillation temperatures of the latter. These nitrogenous organic molecules are either basic, such as amines, anilines, pyridines, acridines, quinolins and their derivatives, or neutral such as for example pyrroles, indoles, carbazoles and their derivatives.

For refiners, basic and neutral nitrogenous compounds are often responsible for the premature deactivation of certain catalysts commonly used in various refining processes. Specifically, these nitrogenous compounds may poison the metallic catalysts of reforming or acid catalysts of isomerization and catalytic cracking. These nitrogenous compounds may also inhibit chemical reactions that occur in hydrosulfurization reactions. Therefore, it may be necessary to remove them prior to this processing because, due to this fact, they may have an indirect polluting effect on atmospheric pollution by increasing the quantity of sulfur oxides discharged into the atmosphere. It is also known that neutral nitrogenous compounds such as pyrrole, indole and carbazole-type nitrogenous compounds and their derivatives present in fuels (diesel fuels or domestic fuels) in the form of nitrogen oxides are one of the direct sources of atmospheric pollution. These two pollutions combined, one direct and the other indirect, promote an increase in the earth's temperature and deterioration of the ozone layer.

In order to slow these phenomena, industrialized countries have established standards, which are at times difficult to observe and which of course affect the sulfur content. So, to achieve the sulfur contents targeted for 2005 and 2010, it is planned to extract or convert nitrogenous compounds beforehand.

J Among the various types of denitrogenation processes known for extracting, or even modifying, the chemical structure of the nitrogenous compounds contained in the petroleum cuts used most often, hydrodenitrogenation consists of placing in contact, at high temperatures and pressures, the petroleum cut with hydrogen and a refractory oxide-based catalyst, in crystalline or amorphous form, supporting metals from Groups VI and VIII of the Periodic Chart of Elements. The catalysts used most are nickel and molybdenum oxide-based catalysts on an alumina base. This process permits cracking of the nitrogenous compounds into ammonia and light hydrocarbons. However, the hydrodenitrogenation processes used do not make it possible to eliminate in a sufficiently complete manner all nitrogenous compounds, in particular aromatic and polyaromatic derivatives called pyrrole, indole group and carbazole-type neutrals.

Other denitrogenation processes propose extracting basic and/or neutral nitrogenous compounds by absorption on a solid generally consisting of an acid or activated carbon contact material, or by liquid/liquid extraction, as described in Patents EP 278 694, FR 2 589 159, U.S. Pat. No. 4,410,421, U.S. Pat. No. 4,521,299 and U.S. Pat. No. 4,529,504. Another process for extracting nitrogenous compounds consists of passing through ion-exchange contact materials as described by G. Marcelin in “Shale oil denitrogenation with ion exchange—Evaluation of ion-exchange absorbents and resin treatment procedures,” Ind. Eng. Chem. Process des. Dev., Vol. 25, pp. 747-756, 1986, or by Patents WO99/67345 and WO 00/64556.

All these extraction processes generally permit the extraction of only a portion of the nitrogenous compounds, with the nitrogenous polyaromatic compounds only being partially extracted and these processes are not always very selective. Because of this, it is not always possible to respect the nitrogen contents established by international standards for the coming years. Furthermore, the problems of total regeneration of the supports or total recovery of the reagents following reaction have yet to be completely resolved.

SUMMARY OF THE INVENTION

Consequently, the applicants became interested in developing a denitrogenation process using polymeric materials, which are stable and inexpensive, very selective in order to retain basic and neutral nitrogenous compounds, which are not soluble in hydrocarbonated compounds, and which can be regenerated at a low cost and for use as a traditional catalyst in industry.

Consequently, the purpose of this invention is a process for the denitrogenation of hydrocarbonated compounds containing nitrogenous compounds characterized by the fact that the hydrocarbonated compounds are placed in contact with at least one polymeric material containing at least one polymer P obtained from at least one non-styrenic monomer A with at least one polar function creating hydrogen bonds with the nitrogenous polyaromatic compounds.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, hydrogen bond is understood as the bond established between at least one hydrogen linked to an electronegative hetero atom present on the polymer and a negative hetero atom present in an acridine, quinolin and pyridine-type nitrogenous hydrocarbon. This bond may also be established between one hydrogen linked to an electronegative heteroatom present in a carbazole, pyrrole and indole-type nitrogenous hydrocarbon, and an electronegative heteroatom present on the polymer.

In the scope of this invention, polymer P may be a homopolymer of monomer A or a copolymer of monomer A with at least one monomer B, with this monomer B able to be any monomer other than monomer A, including a styrenic monomer.

In using this type of polymeric material, it was established that at the same time that it is selective in terms of nitrogen, the absorption of sulfur compounds is limited. Furthermore, the use of a polymer is not unacceptable in the presence of aromatic hydrocarbons because the latter are poorly absorbed by the polymer used in the polymeric material.

According to the most economical method of realizing the invention, the polymeric material may be formed by polymer P alone or supported by a solid from the group formed by another polymer, the refractory oxide mineral supports (silica, alumina or others) and activated carbons, or any other solid, with this solid in divided or aggregate form, being coated by polymer P.

In order to obtain a polymer P adapted to the invention, the monomer A is chosen from the group formed by acrylates, methacrylates, phenols, acrylamides, substituted ethylene oxides, isocyanates and acrylonitriles. These compounds, which may already have polar functions, may or may not be replaced by at least one polar function identical to or different from the first function.

These polar functions are preferably selected from the functions alcohol, ester and ether of type RO, with R being an alkyl group containing 1 to 18 atoms of carbon, amine, starch, imide, nitrile, thiol, thioester, urea, carbamate, thiocarbamate and epoxide.

The polymers P are chosen from the group comprised of poly(acrylates), poly(methacrylates), poly(acrylamides), poly(methacrylamides), poly(ethylene glycols), poly(methanes), formo-phenolic resins and copolymers of these products.

In order for the polymeric material to be sufficiently effective to retain the nitrogenous compounds, polymer P must have 20% to 100% weight in monomer A, preferably 25% to 95% in weight, and even more preferable, 30% to 90% weight from monomer A.

In a preferred method for realizing the invention, monomer A is selected from the acrylates and methacrylates with the functions of ethers and/or epoxides and phenols.

Among the polymers P comprising the preferred monomers A, polymer P is selected from polyglycidylmethacrylate and polyphenols.

To implement the process, a weight ratio of the hydrocarbonated compound to polymer P of at least 1 and preferably greater than 3 is used.

The process according to the invention favorably includes at least a first step of absorbing nitrogenous compounds on the polymeric material, and at least a second step to regenerate the polymeric material P by washing the latter with a polar or aromatic solvent in which the nitrogenous compounds are soluble. The regeneration solvent is preferably selected from toluene, xylene, methanol, ethanol, rape esters or aromatic petroleum cuts, preferably cuts with a high concentration of C₉ to C₁₂ aromatics.

The process according to the invention may preferably be implemented at a temperature between 0 and 300° C., preferably between 0 and 100° C., and under pressure between 105 and 50×10⁵ Pa, preferably at atmospheric pressure.

A second purpose of this invention is the polymeric material used in the denitrogenation process. This polymeric material is characterized by the fact that it does not absorb over 5% in aromatic hydrocarbon weight, preferably not over 1% in weight.

To achieve this low retention of aromatic hydrocarbons, it contains a polymer P obtained from at least one monomer A alone or in combination with at least on monomer B, with polymer P being alone or supported by a solid from the group formed by another polymer, refractory oxide mineral supports and activated carbons, or any other solid, with this solid in a divided or aggregated form being coated by polymer P. Due to this fact, polymer P absorbs at most 5% of its weight in aromatic hydrocarbons, preferably 1% in weight at most.

In the scope of the process of the invention, the extraction of mono- and diaromatics may represent a significant loss in volume and quality of the hydrocarbonated mixtures processed. In order to determine this retention of aromatics by polymer P, 10 g of polymer P and 40 g of diesel fuel are placed in a closed reactor that is shaken and opened after 24 hours of contact. The mixture is then filtered and the polymer P recovered is washed in pentane to remove any paraffin absorbed, then in toluene. After the toluene evaporates, the organic residue obtained is weighed to determine the percentage in weight of aromatics retained compared to the weight of the initial polymer P.

This polymer P may be selected in the group formed by poly(acrylates), poly(methacrylates), poly(acrylamides), poly(methacrylamides), poly(ethylene glycols), poly(methanes), formo-phenolic resins and copolymers of these products. This polymer may be a copolymer. This copolymer may or may not be replaced by at least one polar function from the functions alcohol, ether, ester, amine, starch, imide, nitrile, thiol, thioester, urea, carbamate, thiocarbamate and epoxide. The monomer A is selected from the group formed by acrylates, methacrylates, phenols, acrylamides, substituted ethylene oxides, isocyanates and acrylonitriles. Preferably, the monomer A is selected from acrylates or methacrylates with the functions of ethers and/or epoxide and phenols. Among the polymers P that may be used, the preferred polymers P are selected from polyglycidylmethacrylate and polyphenols.

Favorably, the polymeric material forming the second purpose of the invention can be regenerated by a polar or aromatic solvent common in the trade.

A third purpose of the invention is the use of this denitrogenation process upstream of hydrocarbon treatment processes for which the nitrogenous compounds present are poisons or reaction inhibitors.

Following this description, examples are provided to illustrate the invention, but they are not, however, intended to limit the scope.

EXAMPLE 1

This example describes polymers P, which may be used in the process according to the invention. Their effectiveness with regard to denitrogenation is compared to that of other polymers without polar functions or whose largest components are polystyrenes.

Polymers P are:

polyglycidylmethacrylate or PGMA, hereinafter PG, which is synthesized according to the operating procedure described by Svec, F.; Hradil, J.; Coupek, J.; Kalal, J.; Y. Angew. Makromol. Chem. 48, 135-143, (1975); and

polyphenol marketed by Rohm et Haas under the name Duolite XAD 761, hereinafter Duolite.

The other polymers tested are:

ALDRICH polystyrene, hereinafter PA; and

the sulphonic resin Amberlite IR 120, hereinafter H⁺.

In this example, these polymers are tested in denitrogenation on two types of hydrocarbonated charges, one charge of straight run diesel fuel (GO) and on a LCO (Light Cycle Oil) charge, originating from catalytic cracking. The characteristics of these charges are presented below in Table I. TABLE I Characteristics GO LCO Density (g/cm³) 0.870 0.925 Sulfur (ppm) 14300 15400 Nitrogen (ppm) 360 858 Distillation (° C.) PI 244 129 10% 287 223 50% 325 294 90% 355 365 PF 368 408 Monoaromatics 11.4 18.1 Diaromatics 14.0 35.4 Triaromatics 6.9 5.6* (% in weight) *and 3.8% higher polyaromatics in weight.

The denitrogenation tests were performed in an intermittent reactor with the different polymers or resins, under the following conditions:

ambient temperature: 20° C.;

atmospheric pressure;

charge/P ratio corresponding to 3;

closed reactor;

contact time—24 hours; and

mechanical stirring—400 turns per minute.

10 g of hydrocarbons (charge) and 3.3 g of polymer are placed in a 100 ml reactor equipped with a mechanical stirrer. After reaction, the hydrocarbons are filtered. Then, their nitrogen, sulfur and aromatics contents are measured to determine the polymer's aromatic retention. The results obtained are presented in Table II below. TABLE II Aromatic Final Final Retention** S AS N ΔN Aromatics* (% in Test Agent Charge Level (ppm) (%) (ppm) (%) (mg) weight) 1 PG LCO 1 15100 2 400 53 180 6 2 PG LCO 2 — — 217 75 136 5 3 PG LCO 3 — — 130 85 120 4 4 PG LCO 4 14900 7 52 94 5 H⁺ LCO 5 — — 49 94 6 H⁺ LCO 1 15200 1 804 6 20 1 7 H⁺ LCO 2 726 16 21 1 8 PA LCO 1 14100 8 274 68 507 17 9 PG GO2 1 216 40 125 4 10 PG GO2 2 151 58 11 H⁺ GO2 3 56 84 12 H⁺ GO2 1 250 31 13 H⁺ GO2 2 226 37 14 Duolite GO2 1 13400 1 175 51 84 3 15 Duolite LCO 1 15100 2 520 40 *Retention of aromatics absorbed by the polymer: corresponds to the ratio of grams of aromatic compounds absorbed per kilogram of polymer P. **Aromatics: corresponds to the aromatic materials present in the hydrocarbons, expressed in mg.

According to this table, when one wishes to denitrogenate LCO in several steps (tests 1-4), a regular decrease in the nitrogen content (>90%) is observed. When this charge is placed in contact with the resin H⁺ (test 5), a perceptible decrease in the nitrogen rate is not observed. Similarly, after two LCO or GO denitrogenation steps (tests 6-7 or 12-13) with resin H⁺ present, a similar denitrogenation plateau of 16% or 37% is achieved, respectively. Comparatively, when the LCO or GO is placed in contact with the PG, the denitrogenation after two steps is 75% and 58%, respectively, and this denitrogenation may be improved. By repeating other steps on another polymer according to the invention, Duolite, after one denitrogenation step, there is a minimum 40% decrease in nitrogen.

It must also be noted that the retention of aromatics in polystyrene PA is approximately 17% while it is less than or equal to 6% in weight with the polymer from the invention.

EXAMPLE 2

This example shows that the polymers according to the invention, in particular PG, are able to be completely regenerated.

With this purpose, we measured the effectiveness of polymer PG, used to denitrogenate a GO diesel fuel charge or a LCO charge after regeneration of polymer P by toluene, following several cycles of usage and regeneration.

The GO and LCO were denitrogenated according to the conditions described in Example I. After each first denitrogenation step, polymer PG was regenerated in toluene in a soxhlet. Then, it was reused in denitrogenation. The results are shown in Table III below.

The conditions for the regeneration procedure are the following:

atmospheric pressure;

toluene reflux temperature; and

contact time at most 24 hours (until desorption of all nitrogenous compounds retained on the PG). TABLE III Final N Regeneration Charge (ppm) ΔN (%) 1 LCO 400 53 2 LCO 420 51 3 LCO 465 46 4 LCO 412 52 1 GO 216 40 2 GO 219 39 3 GO 240 33 4 GO 232 36

This table establishes that after each regeneration, the same denitrogenation rates are achieved, after a first denitrogenation step, as the PG that has been regenerated one or several times. This confirms that polymer P is indeed able to be generated without modifying its nitrogen selectivity. 

1. A process for denitrogenation of hydrocarbonated compounds comprising basic and/or neutral nitrogenous hydrocarbonated compounds, comprising placing the hydrocarbonated compounds in contact with a polymeric material comprising at least one polymer P obtained from at least one non-styrenic monomer A with at least one polar function generating hydrogen bonds with the nitrogenous hydrocarbonated compounds.
 2. The process according to claim 1, wherein polymer P is a homopolymer of A or a copolymer of A with at least one monomer B different from monomer A.
 3. The process according to claim 1, wherein the polymeric material is formed by polymer P alone or supported by a solid, with this solid, in divided or aggregate form, being coated by polymer P.
 4. The process according to claim 1, wherein monomer A is selected from the group consisting of acrylates, methacrylates, phenols, acrylamides, substituted ethylene oxides, urethanes, isocyanates and acrylamides substituted or not by at least one polar function.
 5. The process according to claim 1, wherein the at least one polar function of polymer A is selected from the group consisting of alcohol, ester and ether of type RO, with R being selected from the group consisting of an alkyl group containing 1 to 18 atoms of carbon, amine, starch, imide, nitrile, thiol, thioester, urea, carbamate, thiocarbamate and epoxide.
 6. The process according to claim 1, wherein polymer P comprises 20 wt % to 100 wt % of monomer A.
 7. The process according to claim 1, wherein polymer P is selected from the group consisting of poly(acrylates), poly(methacrylates), poly(acrylamides), poly(methacrylamides), poly(ethylene glycols), poly(methanes), formo-phenolic resins and copolymers of these products.
 8. The process according to claim 1, wherein monomer A is selected from the group consisting of acrylates and methacrylates with ether and/or epoxide functions and phenols.
 9. The process according to claim 1, wherein polymer P is selected from the group consisting of polyglycidylmethacrylates and polyphenols.
 10. The process according to claim 1, wherein the denitrogenation reaction is carried out at a temperature between 0 and 300° C., and under pressure between 10⁵ and 50×10⁵ Pa.
 11. The process according to claim 1, wherein the weight ratio of the hydrocarbonated compound to polymer P is at least
 1. 12. The process according to claim 1, further comprising at least a first step of absorbing the nitrogenous compounds on the polymeric material, and at least a second step of regenerating the polymeric material by washing it with a polar or aromatic solvent in which the nitrogenous compounds are soluble.
 13. The process according to claim 12, wherein, in the second step, the solvent is selected from the group consisting of toluene, xylene, ethanol and aromatic petroleum cuts.
 14. A polymeric material comprising at least one polymer P obtained from at least one non-styrenic monomer A, wherein the polymeric material is able to absorb at most 6 wt % of aromatic hydrocarbons in the process of claim
 1. 15. The polymeric material according to claim 14, comprising one polymer P obtained from at least one monomer A alone or in combination with at least one monomer B, with polymer P being alone or supported by a solid, with this solid, in divided or aggregated form, being coated by polymer P, with this polymer P not absorbing over 6 wt % of aromatic hydrocarbons.
 16. The polymeric material according to claim 14, wherein monomer A is selected from the group consisting of acrylates, methacrylates, phenols, acrylamides, substituted ethylene oxides, and isocyanates, which may or may not be substituted by at least one polar function selected from the group consisting of alcohol, ether, ester, amine, starch, imide, nitrile, thiol, thioester, urea, carbamate and thiocarbamate and epoxide.
 17. The polymeric material according to claim 16, wherein monomer A is selected from the group consisting of acrylates and methacrylates with ether and/or epoxide functions and phenols.
 18. The polymeric material according to claim 14 wherein polymer P is selected from the group consisting of poly(acrylates), poly(methacrylates), poly(acrylamides), poly(methacrylamides), poly(ethylene glycols), poly(methanes), formo-phenolic resins and copolymers of these products.
 19. The polymeric material according to claim 14, wherein polymer P is selected from the group consisting of polyglycidylmethacrylate and polyphenols.
 20. A hydrocarbon processing process, comprising employing the process of claim 1 upstream from a part of the hydrocarbon processing process for which the nitrogenous compounds present are poisons or reaction inhibitors.
 21. The hydrocarbon processing process of claim 20, wherein the process of claim 1 is upstream from at least one of processes selected from the group consisting of reforming, isomerization, catalytic cracking and the desulfurization.
 22. The process according to claim 2, wherein monomer B is a styrenic monomer.
 23. The process according to claim 3, wherein the solid is selected from the group consisting of another polymer, refractory oxide mineral supports, and activated carbon.
 24. The process according to claim 6, wherein polymer P comprises 25 wt % to 95 wt % of monomer A.
 25. The process according to claim 6, wherein polymer P comprises 30 wt % to 90 wt % of monomer A.
 26. The process according to claim 10, wherein the denitrogenation reaction is carried out at a temperature between 0 and 100° C.
 27. The process according to claim 10, wherein the denitrogenation reaction is carried out at atmospheric pressure.
 28. The process according to claim 11, wherein the weight ratio of the hydrocarbonated compound to polymer P is greater than
 3. 29. The process according to claim 13, wherein, in the second step, the solvent comprises aromatic petroleum cuts with a high concentration of C₉ to C₁₂ aromatics.
 30. The polymeric material of claim 14, wherein the polymeric material is able to absorb at most 1 wt % of aromatic hydrocarbons in the process of claim
 1. 31. The polymeric material according to claim 15, wherein the solid is selected from the group consisting of another polymer, refractory oxide mineral supports and activated carbon.
 32. The polymeric material according to claim 15, wherein polymer P does not absorb over 1 wt % of aromatic hydrocarbons. 